期刊
ENERGY STORAGE MATERIALS
卷 47, 期 -, 页码 44-50出版社
ELSEVIER
DOI: 10.1016/j.ensm.2022.01.047
关键词
Sodium-ion batteries; Fe-Mn based layered oxide cathodes; Solid-solution reaction; Oxygen redox; Na-site doping
资金
- National Natural Science Foundation of China [22075016, 21805007, 22075067]
- Fundamental Research Funds for the Central Universities [FRF-TP-20-020A3, FRF-TP-18-091A1]
- Guangdong Basic and Applied Basic Research Foundation [2019A1515110104]
- 111 Project [B170003, B12015]
The research presents a new approach to achieving high-energy and long-life layered oxide cathodes in sodium-ion batteries by developing a novel P2-NCLFMO material and realizing a complete solid-solution sodiation/desodiation behavior over a wide voltage range. The P2-NCLFMO cathode exhibits outstanding rate capability and cycling performance, and when paired with a hard carbon anode, it delivers a promising energy density for sodium-ion full batteries.
Iron/manganese-based layered transition-metal oxides have attracted numerous attentions as promising cathodes for sodium-ion batteries (SIBs) due to their high theoretical capacities and abundant reserves, yet they still suffer from detrimental phase transitions and fast capacity fading. Herein, we realize a complete solid-solution sodiation/desodiation behavior over a wide voltage range of 1.5-4.3 V in a novel P2-Na0.75Ca0.05Li0.15Fe0.2Mn0.6O2 (P2-NCLFMO) cathode material, where cationic and anionic redox reactions synergistically provide charge compensation. Li ions in transition-metal (TM) sites not only trigger the oxygen redox activity, but also increase the Na content for stabilizing the P2-structure at high voltage and weaken the Jahn-Teller effect by diluting the Mn3+ concentration; Ca ions in Na sites serve as pillars to stabilize the layered structure and alleviate the lattice oxy-gen release. The complete solid-solution reaction in the wide voltage range ensures both rapid Na+ diffusivity and small volume variation. Therefore, the P2-NCLFMO cathode shows outstanding rate capability (183 mAh g(-1) at 0.1C in comparison with 49.9 mAh g(-1) at 20C) and respectable cycling performance (76% capacity retention after 150 cycles at 1C). Additionally, the prototype Na-ion full battery constructed by the P2-NCLFMO cathode and hard carbon anode delivers a promising energy density of 246.3 Wh kg(-1). This work provides a new platform for achieving high-energy and long-life layered oxide cathodes involving cationic and anionic redox by eliminating the irreversible phase transitions.
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